If you have more than one VA disability rating, you have probably noticed the numbers do not add up. A 30 percent rating and a 20 percent rating do not make 50 percent. At the VA, they make 40. That is not a mistake. It is how the combined ratings system is designed, and once you see the logic, the numbers stop being mysterious.
This guide explains what a rating is, how the VA combines multiple ratings, why rounding matters more than most veterans realize, and how to estimate where your own combined rating could land.
What a VA disability rating is
The VA rates each service-connected condition on a scale from 0 to 100 percent, in increments of 10, based on severity. The criteria come from the VA’s rating schedule (38 CFR Part 4), which assigns each condition a diagnostic code with specific requirements for each percentage level. Your monthly compensation is driven by your combined rating across all service-connected conditions, and the VA publishes its current compensation rate tables on VA.gov.
Why ratings do not simply add
The VA treats you as starting at 100 percent efficient, meaning not disabled. Each rating then applies to whatever efficiency remains, rather than adding to the whole. That single idea is the entire trick behind VA math.
Worked example 1: 30 + 20. Start at 100 percent efficient. A 30 percent rating leaves you 70 percent efficient. The next rating, 20 percent, applies to that remaining 70, and 20 percent of 70 is 14. Add that to the first 30 and the combined value is 44. The VA then rounds to the nearest 10, so 44 becomes a 40 percent combined rating.
Worked example 2: 50 + 30. Start at 100. A 50 percent rating leaves 50. A 30 percent rating takes 30 percent of that remaining 50, which is 15. The combined value is 65, and 65 rounds to 70 percent.
The order of the ratings does not change the outcome. The VA lists them from most to least severe by convention, but the math lands in the same place either way. This is also why stacking several small ratings never quite reaches 100 percent: each new rating is a percentage of an ever-shrinking remainder.
The rounding rule cuts both ways
Combined values round to the nearest 10. A 44 becomes a 40, while a 65 becomes a 70. That means a single additional 10 percent rating can be worth far more than it looks on paper if it pushes your combined value across a rounding line, and it also means two veterans with similar conditions can land on different sides of a threshold.
The bilateral factor
When disabilities affect both arms, both legs, or paired skeletal muscles, the VA applies the bilateral factor: it combines those ratings, adds 10 percent of that combined value, and then folds the result into the rest of the calculation (38 CFR 4.26). It is a modest boost, but for veterans with conditions on both sides of the body it is worth knowing about.
Why the combined rating matters beyond the monthly check
Certain benefits key off specific combined ratings. For example, veterans with a combined rating of 30 percent or higher can receive additional compensation for eligible dependents. The difference between a 40 and a 50, or an 80 and a 90, is not just dollars each month; it can change what you qualify for. This is also why secondary conditions matter so much, which we cover in a separate guide.
Estimate before you file
Doing this math by hand across four or five conditions gets tedious fast, and small mistakes compound. VA Champion’s free estimate runs the combined ratings math for you: enter your conditions, see where your combined rating could land, and use the guided platform to organize and self-file. The VA always makes the final call on ratings, but you should never walk into the process blind.
Related reading: How to File a VA Disability Claim Yourself: A Step-by-Step Guide
Frequently asked questions
Why is my combined rating lower than the sum of my ratings? Because each rating applies to your remaining efficiency, not to the whole. The combined value is then rounded to the nearest 10.
Does the order of my ratings matter? No. The combined value comes out the same regardless of the order in which the ratings are combined.
What is the bilateral factor? An extra 10 percent of the combined value of ratings that affect paired limbs, added before those ratings are folded into the overall calculation.
Where do I find the current compensation rates? On the veterans disability compensation rates page at VA.gov. Rates typically adjust annually with the cost-of-living adjustment.
VA Champion, LLC provides self-help software and general educational information about the VA disability process. This article is educational only. It is not legal or medical advice, and it is not a substitute for an accredited representative. The VA decides all ratings, approvals, and timelines.
